OA explained

OA, O.A., Oa, or oa may refer to:

Arts and entertainment

Oa (comics), a fictional planet in the DC Comics universe
The OA, a television series
OpenArena, a video game
Opie and Anthony (often "O&A"), a radio show
Oriental Adventures, a Dungeons & Dragons sourcebook
Orion's Arm, a science fiction project

Businesses and organisations

Obavještajna agencija, the Croatian Intelligence Agency
Office administration
Oficina Anticorrupción, an Argentine law enforcement agency
Olympic Air (IATA code OA)
Opera Australia, an opera company
Opportunitas aequa, a Canadian organization
Overeaters Anonymous
Oxford Academy (California), a high school
Orbital ATK, an aerospace company

People

Ma'am OA, nickname of Andrea Veneracion, founder of the Philippine Madrigal Singers
Oskar Andersson, Swedish cartoonist who uses the pen name O.A.

Places

Oa (Attica), a deme of ancient Attica
Ocean Acres, New Jersey, United States
Orakzai Agency, Pakistan
The Oa, Scotland, United Kingdom

Honors

Order of Australia, a formal honour
Order of the Arrow, the honor society of Scouting America

Science and technology

Office automation
Oleic acid, a fatty acid
Open access, the free online availability of digital content from scholarly sources
Operational amplifier, an electronic component
Operational analysis, more generally called "operational research", a branch of applied mathematics
Osteoarthritis, a disease
Length overall (also o/a, o.a. or oa), an abbreviation for overall, used when describing the length of a ship
Oxford Archaeology

Other uses

Oa (digraph)
Obituaries Australia, an online database of obituaries
Office Action, a communication from the U.S. Patent and Trademark Office
Old Alleynian, an old boy of Dulwich College
Old Albanian, an old boy of St Alban School, St Albans
Order of Appearance, a synonym for Order of battle
Output area, an area of approximately 100 households, derived from the UK Census

See also